1. Field of the Invention
The present invention relates to a cutter mechanism that cuts a recording sheet while sandwiching the recording sheet by causing a movable blade to slide with respect to a fixed blade, and to a printer with a cutter including the cutter mechanism.
2. Description of the Related Art
Nowadays, a great number of various types of thermal printers, which performs printing by pressing a thermal head against a special recording sheet that changes color when heat is applied thereto, are provided. In particular, use is suitably made in printing of receipts, tickets, and the like because smooth character printing and colorful graphic printing are possible without using toner, ink, and the like.
As represented by the thermal printers, numerous printers with a cutter provided with a cutter mechanism for cutting the printed recording sheet are known. The printer with a cutter is used by being incorporated in, for example, a cash register, a mobile terminal device, and the like.
Typically, the cutter mechanism is configured by a fixed blade and a movable blade that is slidable. When cutting the recording sheet, the movable blade is slid so as to ride on the upper surface or the lower surface of the fixed blade. Both blades are then allowed to sandwich and cut the recording sheet as if a pair of scissors.
In general, the fixed blade is configured to have the cutting edge side supported so as to be swingable up and down, and is biased so that the cutting edge is pushed upward by a biasing portion such as a coil spring with respect to the movable blade. Thus, when the movable blade slides, both blades are brought into contact with each other at an appropriate contacting pressure. As a result, such design is made so that the recording sheet can be cut neatly.
Further, the movable blade is typically formed into a substantially V-shape in top view, and is designed so as to come into contact with the fixed blade at right and left two points when riding on the fixed blade. Therefore, in accordance with slidable movement of the movable blade, the right and left two contact points move along a width direction of the recording sheet from both sides toward a middle of the recording sheet. Thus, it is possible to sharply cut the recording sheet from both right and left sides thereof without skew.
However, in order to sharply cut the recording sheet from both right and left sides toward the middle thereof, it is necessary to equally subject the fixed blade and the movable blade to press-contact at the right and left two contact points. If a difference is seen between press-contact forces, there is a fear that an uncut portion, etc. are left, or a fear that a cut end surface is distorted.
In this context, as a cutting device meeting such need, there is known a cutting device capable of performing correction so that a press-contact force of the fixed blade with respect to the movable blade is equalized in a blade width direction (see Japanese Patent No. 3801423).
The cutting device is briefly described. First, on a root portion side of the fixed blade (on an opposite side of the cutting edge), two or more projecting support portions are formed. Meanwhile, in a fixed blade holding member for holding the fixed blade, receiving holes into which the support portions are inserted are formed according to the number of the support portions. The receiving holes are formed to have a size larger than that of the support portions in order to secure plays between the inserted support portions and the receiving holes.
Further, the fixed blade is held by the fixed blade holding member in a state in which the support portions are swingably inserted in the receiving holes. In this case, the fixed blade is biased by a plate spring, and the cutting edge side is pressed against the movable blade.
With this configuration, when the movable blade rides on the fixed blade, due to a biasing force applied by the plate spring, the fixed blade and the movable blade are held in press-contact with each other at an appropriate contacting pressure. In this case, the plays are secured between the support portions and the receiving holes, and hence the fixed blade can slightly swing in the blade width direction. Therefore, even if a difference is seen between the press-contact forces at the right and left two contact points, the fixed blade swings in the blade width direction, and it is possible to perform correction so that the press-contact forces are equalized.
However, because the two or more support portions inserted in the receiving holes are formed on the fixed blade, it has been difficult to expect a high swinging property in the blade width direction. In other words, with use of the plays secured between the support portions and the receiving holes, the fixed blade can be caused to swing in the blade width direction. However, because the two or more support portions are formed, it is difficult to make the most of each of the plays, and a swinging amount is necessarily restricted.
Therefore, the high swinging property in the blade width direction cannot be expected, and it has been sometimes difficult to equalize the press-contact forces at the right and left two contact points during cutting from beginning to end. Consequently, there remains a fear that an uncut portion, etc are still left when the recording sheet is cut.
Further, though the fixed blade is typically manufactured by punching with use of a die, a die shape is complex because two or more support portions are formed. In particular, as a material for the fixed blade, a metal material with high hardness is often adopted, and hence a high load tends to act on the die during punching. Therefore, as the die shape becomes more complex and fine, chips and cracks are more likely to occur, and the life of the die is more likely to decrease. As a result, a manufacturing cost of the fixed blade is influenced, which leads to an increase in the cost of the fixed blade. In view of the foregoing, a fixed blade having a simple a shape as possible is presently desired.